Making new Evolution Stones using Hex Maniac Advance by replacing Unused Item slots

[DevidraGaming]

Spoiler:

So, you want to make a new evolution stone, but you don't know how to expand the item table? No problem, you don't actually need to! There are plenty of unused item slots in FireRed and Emerald that can be edited to make a functioning evolution stone. Images are in spoilers so as to shorten the thread.

In this tutorial, I'll be using an unedited FireRed 1.0 rom, but with some experimentation it's worked with every gen III rom I've tested.
So to start, open up HMA, and open the rom you intend to add the evo stone to.

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In the first menu, select data, then items, then stats:

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Scroll down to the evolution stones, Sun Stone should come first. Select the ??????? item just above it (Or any around it, but for this one I did that one. This tutorial will work for multiple stones, but to be safe, stick with the unused items around the other evo stones, because not all of the unused items support item effects, which you need for this.)

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Set the name to whatever you want it to be, in this tutorial I'll be making the Ice Stone from newer games. Set the "index" value to 92 (If you're editing the item directly above the Sun Stone. If not, use the used items around the slot you're using to figure it out, the index items don't change, if there's 7 unused items in between two used, there will be a +7 difference between the first item's index and the second item's.). The price can be whatever you want it to be. Since the existing stones (Not counting the Moon Stone, which can't be sold) use the price 2100, that's what I've set mine to.

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In the description field, select Repoint > This One. This will repoint the description so that you can make it unique, instead of just ?????

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Before repoint and edit:

After repoint and edit:

The keyitemvalue and bagkeyitem values don't need to be changed, and neither does the pocket value. Set the type value to 1, and set the field effect to 0A1751.

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Repoint the sprite and palette, by using Repoint > This One again. Now, you can either import an already created sprite or make your own through HMA's Image Editor. Keep in mind you are limited to 15 colors in the sprite, as well as one to make a transparent background. I imported an already created Ice Stone sprite in this case.

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Before repoint and import:

After repoint and import:

Here's some good news: You're almost done! Last step is to create the item effects and copy them from another evo stone.
At the very bottom of the edit menu for the item, there is a data table labelled data.item.effects that is currently set to <null>
Select "Create new data," and then take the effect data from one of the existing stones, and copy/paste it into the new one.

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Before new data:

After new data:

And that's it! Your evolution stone should be finished, and you can now set it to be used for evolutions.

 

[Drake Baku]

Certainly going to use this, thanks